A micro-channel device includes one or more micro channels through which one or more small volumes of samples are routed for processing and/or analysis. An example of such a device includes a sample carrier such as a biochip, a lab-on-a-chip, and/or other micro-channel device. An application in which a micro-channel device has been used is DNA sequencing. DNA sequencing, generally, is a method for determining an order of the nucleotide bases (i.e., adenine, guanine, cytosine, and thymine) of DNA in a sample.
For DNA sequencing, DNA in a sample is lysed, producing DNA fragments of sequences of the four nucleotides. The fragments are replicated through polymerase chain reaction (PCR) and labeled with target specific fluorescent dyes (e.g., one for each nucleotide base), each dye having its own fluorescent emission characteristic (e.g., wavelength, frequency, energy and color). The labeled fragments are separated by size through electrophoresis.
An optical system is used to illuminate the separated fragments with an excitation signal. The excitation signal is absorbed by the dyes of the fragments, and the dyes fluoresce based on their respective fluorescent emission characteristics. The optical system detects the fluorescent emission and generates signals indicative thereof. The signals are processed to identify the nucleotides of and sequence the DNA.
Generally, when an optical system is installed in a DNA sequencer, an optical performance of the installed optical system is not known, and the performance thereof may not satisfy given performance criteria, for example, due to optical misalignment, mismatched optical components, etc. In view of the foregoing, there is an unresolved need to determine an optical performance of the optical system installed in a DNA sequencer.